:root {
  --osu-scarlet: #bb0000;
  --osu-scarlet-dark: #8f0000;
  --osu-gray: #666666;
  --osu-gray-dark: #2b2b2b;
  --qiskit-purple: #6929c4;
  --bg: #ffffff;
  --bg-alt: #f7f6f8;
  --text: #222222;
  --text-muted: #5b5b5b;
  --border: #e4e2e6;
  --radius: 10px;
  --max-width: 1080px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
}

img {
  max-width: 100%;
}

a {
  color: var(--qiskit-purple);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* ---------- Header / Nav ---------- */

.site-header {
  background: var(--osu-scarlet);
  color: #fff;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.85rem 1.5rem;
  max-width: var(--max-width);
  margin: 0 auto;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-weight: 700;
  font-size: 1.1rem;
  color: #fff;
}

.brand:hover {
  text-decoration: none;
  opacity: 0.9;
}

.brand-mark {
  width: 34px;
  height: 34px;
  border-radius: 8px;
  background: var(--qiskit-purple);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  flex-shrink: 0;
}

.nav-links {
  display: flex;
  gap: 1.5rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav-links a {
  color: #fff;
  font-weight: 500;
  opacity: 0.9;
  padding: 0.25rem 0;
  border-bottom: 2px solid transparent;
}

.nav-links a:hover,
.nav-links a.active {
  opacity: 1;
  text-decoration: none;
  border-bottom-color: #fff;
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  color: #fff;
  font-size: 1.6rem;
  cursor: pointer;
}

@media (max-width: 720px) {
  .nav-toggle {
    display: block;
  }

  .nav-links {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--osu-scarlet-dark);
    flex-direction: column;
    gap: 0;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.25s ease;
  }

  .nav-links.open {
    max-height: 400px;
  }

  .nav-links li {
    border-top: 1px solid rgba(255, 255, 255, 0.15);
  }

  .nav-links a {
    display: block;
    padding: 0.9rem 1.5rem;
    border-bottom: none !important;
  }
}

/* ---------- Hero ---------- */

.hero {
  background: linear-gradient(135deg, var(--osu-scarlet) 0%, var(--osu-scarlet-dark) 55%, var(--qiskit-purple) 130%);
  color: #fff;
  padding: 4.5rem 1.5rem 4rem;
  text-align: center;
}

.hero h1 {
  font-size: clamp(2rem, 5vw, 3rem);
  margin: 0 0 0.75rem;
}

.hero p.subtitle {
  font-size: 1.2rem;
  opacity: 0.95;
  max-width: 640px;
  margin: 0 auto 2rem;
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 1.5rem;
  margin-bottom: 2.25rem;
  font-weight: 500;
}

.hero-meta span {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  justify-content: center;
}

/* ---------- Buttons ---------- */

.btn {
  display: inline-block;
  padding: 0.8rem 1.75rem;
  border-radius: 999px;
  font-weight: 600;
  border: 2px solid transparent;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.btn:hover {
  text-decoration: none;
  transform: translateY(-2px);
}

.btn-primary {
  background: #fff;
  color: var(--osu-scarlet);
}

.btn-primary:hover {
  box-shadow: 0 6px 16px rgba(0, 0, 0, 0.2);
}

.btn-outline {
  background: transparent;
  border-color: #fff;
  color: #fff;
}

.btn-purple {
  background: var(--qiskit-purple);
  color: #fff;
}

.btn-purple:hover {
  box-shadow: 0 6px 16px rgba(105, 41, 196, 0.35);
}

/* ---------- Sections ---------- */

section {
  padding: 4rem 0;
}

section.alt {
  background: var(--bg-alt);
}

.section-header {
  text-align: center;
  max-width: 640px;
  margin: 0 auto 2.5rem;
}

.section-header h2 {
  font-size: 2rem;
  margin-bottom: 0.5rem;
  color: var(--osu-gray-dark);
}

.section-header p {
  color: var(--text-muted);
}

.eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--qiskit-purple);
}

/* ---------- Cards / Grids ---------- */

.grid {
  display: grid;
  gap: 1.5rem;
}

.grid-3 {
  grid-template-columns: repeat(3, 1fr);
}

.grid-2 {
  grid-template-columns: repeat(2, 1fr);
}

@media (max-width: 800px) {
  .grid-3,
  .grid-2 {
    grid-template-columns: 1fr;
  }
}

.card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
}

.card h3 {
  margin-top: 0;
  color: var(--osu-gray-dark);
}

.card .icon {
  font-size: 1.75rem;
  margin-bottom: 0.75rem;
  display: block;
}

/* ---------- Schedule ---------- */

.schedule-day {
  margin-bottom: 2.5rem;
}

.schedule-day h3 {
  color: var(--osu-scarlet);
  border-bottom: 2px solid var(--border);
  padding-bottom: 0.5rem;
}

.schedule-item {
  display: flex;
  gap: 1.25rem;
  padding: 1rem 0;
  border-bottom: 1px solid var(--border);
}

.schedule-item:last-child {
  border-bottom: none;
}

.schedule-time {
  flex: 0 0 130px;
  font-weight: 700;
  color: var(--qiskit-purple);
}

.schedule-details strong {
  display: block;
  color: var(--osu-gray-dark);
  margin-bottom: 0.15rem;
}

.schedule-details span.tag {
  display: inline-block;
  margin-top: 0.4rem;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  padding: 0.15rem 0.6rem;
  border-radius: 999px;
  background: rgba(105, 41, 196, 0.1);
  color: var(--qiskit-purple);
}

/* ---------- Team / Sponsors ---------- */

.people-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 1.5rem;
}

.person {
  text-align: center;
}

.avatar {
  width: 100px;
  height: 100px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--osu-scarlet), var(--qiskit-purple));
  margin: 0 auto 0.75rem;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-weight: 700;
  font-size: 1.4rem;
}

.person h4 {
  margin: 0 0 0.15rem;
}

.person span {
  color: var(--text-muted);
  font-size: 0.9rem;
}

.sponsor-tier {
  margin-bottom: 2.5rem;
}

.sponsor-tier h3 {
  text-align: center;
  color: var(--osu-gray-dark);
}

.sponsor-logos {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 2rem;
  margin-top: 1.5rem;
}

.sponsor-logo-placeholder {
  width: 180px;
  height: 90px;
  border: 2px dashed var(--border);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  font-size: 0.85rem;
  text-align: center;
  padding: 0.5rem;
}

/* ---------- Register ---------- */

.register-box {
  max-width: 640px;
  margin: 0 auto;
  text-align: center;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 3rem 2rem;
}

.register-box .btn {
  margin-top: 1rem;
}

.faq-item {
  margin-bottom: 1.5rem;
}

.faq-item h4 {
  margin-bottom: 0.25rem;
  color: var(--osu-gray-dark);
}

/* ---------- Resources ---------- */

.resource-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.resource-list li {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem 1.5rem;
  margin-bottom: 1rem;
  background: #fff;
}

.resource-list a {
  font-weight: 600;
  font-size: 1.05rem;
}

.resource-list p {
  margin: 0.35rem 0 0;
  color: var(--text-muted);
}

/* ---------- Footer ---------- */

.site-footer {
  background: var(--osu-gray-dark);
  color: #cfcfcf;
  padding: 2.5rem 1.5rem;
  text-align: center;
  margin-top: 3rem;
}

.site-footer a {
  color: #fff;
}

.footer-links {
  display: flex;
  gap: 1.5rem;
  justify-content: center;
  margin-bottom: 1rem;
  flex-wrap: wrap;
}

.footer-social {
  margin-bottom: 1rem;
}

.footer-fine-print {
  font-size: 0.85rem;
  color: #999;
}

/* Event logo in the nav bar — hidden automatically if assets/logo.png is missing */
.brand-logo {
  height: 32px;
  width: auto;
  margin-right: 0.5rem;
  vertical-align: middle;
}

/* Hide the fallback atom glyph once a real logo loads */
.brand-logo + .brand-mark {
  display: none;
}
/* Outline buttons on white sections need dark text, not white */
section:not(.hero) .btn-outline {
  border-color: var(--osu-scarlet);
  color: var(--osu-scarlet);
}

section:not(.hero) .btn-outline:hover {
  background: var(--osu-scarlet);
  color: #fff;
}
/* Photos inside the avatar circles */
.avatar img {
  width: 100%;
  height: 100%;
  border-radius: 50%;
  object-fit: cover;
}